To maximise your miles income you need to put all spending on your White Amex, if you spend £10k in a year (amex spend only) you will get 1 upgrade voucher so you pay for economy miles but get PE seats, this can be split into singles and used one way for both of you.
The gold Amex is worth signing up for it does have a £140 fee in the 2nd year, but sign up is worth 22k miles if you get someone to refer you. Once you have met the sign up requirements refer your partner, wait for the referral miles, transfer your miles out to Flying club and close it down, wait 6 months and repeat.